I bought a used hard drive off of Ebay and hooked it up. The drive is not displayed in "My Computer" but is visible in "Device Manager." It is also visible in BIOS as a WD205AA. Any ideas for how to get this hard drive working?

It is possible that the drive may be running in a different file system than your operating system. For example if the hard drive in question is running NTFS and you are in Windows ME, it isn't going to show. You will need to format the drive in the correct FS in order to use it. What OS are you currently running?

The dude may have removed all partitions before he sent it to you. Are you running Windows XP? If you are go to Control Panel -> Administrative Tools -> Computer Management -> Disk Management and find the drive there, see what it says.

If it says unallocated or some such right click on it and do new partition, follow the wizard there.

If you are confused, of that doesn't help post back.

I am running XP and the hard drive does not show up under Disk Management. How would I go about formatting a hard drive that I can't find?

Create a Boot Disk and run FDISK........

then format the sucker too.....job done

There are two cables attached to the motherboard right. One is attached to your HDD and another to the CD- ROM . If the HDD isn't working when attched to the first cable i.e to the cable where your HDD is attached, try attaching it to the cable of the CD-ROM ( try to both the ports ).